Experts meet to decide Pluto fate, Finally we'll know what a 'planet' is... |
Experts meet to decide Pluto fate, Finally we'll know what a 'planet' is... |
Aug 14 2006, 06:06 AM
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Member Group: Members Posts: 295 Joined: 2-March 04 From: Central California Member No.: 45 |
-------------------- Eric P / MizarKey
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Aug 16 2006, 07:47 PM
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Senior Member Group: Moderator Posts: 3233 Joined: 11-February 04 From: Tucson, AZ Member No.: 23 |
now that I have heard the rational for the double planet scenario (like Pluto-Charon), I am a bit more confortable with it. Basically, they are using historical prescedent to influence this part of the definition. For example, a binary star system may consist of two vastly different worlds, say a blue giant and a red dwarf. The barycenter is located outside either star, but most importantly, both are considered stars. It isn't one blue giant star, and a red dwarf planet (or some such). They are just two stars in the same system. one scenario contemplated was the possibility of two extrasolar gas giants orbiting around a common center of mass. Are both planets? Is only the largest a planet?
-------------------- &@^^!% Jim! I'm a geologist, not a physicist!
The Gish Bar Times - A Blog all about Jupiter's Moon Io |
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Aug 16 2006, 07:58 PM
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Senior Member Group: Members Posts: 2530 Joined: 20-April 05 Member No.: 321 |
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Aug 16 2006, 08:08 PM
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Member Group: Members Posts: 809 Joined: 11-March 04 Member No.: 56 |
And, as I mentioned before, what about a very planetlike body (Earth, Saturn -- take your pick) that is in deep space, not orbiting a star. If it's not a planet, what the heck is it? Or if it were orbiting an object that is not a star (a pulsar). I feel some discomfort with the idea of a dark object in the interstellar void being called a planet; both on historical grounds, and because such an object, in permanent darkness, conditions of extreme cold, and not gravitationally bound to another object, couldn't be expected to behave like any of the objects we know as planets. We don't have names for such objects because they haven't been observed. As hypotheticals, I'd prefer "dark object" or, really, anything other than "planet". As for the Charon question, why not extend the "planetary" honor to planet-sized satellites as well? Just call them "satellite planets" or the like. There's historical justification for this: the Moon, of course, was once considered a planet, and Galileo, Huygens, and Cassini dubbed their finds "planets" before the term "satellite" came to be generally accepted. |
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